In situ temperature compensation for thin-film force sensors

Advanced digitalization and automation of production processes as well as the predictive maintenance of machine elements, require reliable sensors to collect in situ data as input for control processes. The quality and reliability of these data are crucial for the successful implementation and acceptance of such solutions. Therefore, sensors that can be integrated and measure as close as possible to the signal origin are of high value. In many applications, force or pressure is a key variable. Precise measurements often need effective temperature compensation, which can be challenging when high and locally concentrated temperature gradients occur (e.g., in cutting tools of machining operations). Therefore, a new thin-film sensor design is presented with a diamond-like carbon (DLC)-based temperature sensor placed directly beneath a manganin-based force sensor to enable in situ temperature compensation of the force sensor. The setup and manufacturing of the thin-film system on steel washers are presented. Temperature compensation is successfully demonstrated in an industrial environment by integrating the sensory washer beneath a cutting insert. Calibration and measurements of the cutting force in a turning process are performed, and a process-control use case is implemented.